add main.rs

Signed-off-by: Hiroyuki Moriya <41197469+Gekko0114@users.noreply.github.com>

experiment/selinux/Cargo.toml

@@ -12,6 +12,7 @@ autoexamples = true
 keywords = ["youki", "container", "selinux"]
 
 [dependencies]
+anyhow = "1.0.86"
 nix = { version = "0.29.0", features = ["process", "fs", "socket"] }
 rustix = { version = "0.38.34", features = ["fs"] }
 tempfile = "3.10.1"

experiment/selinux/README.md

@@ -6,3 +6,7 @@ Therefore, this PR will implement xattr in Rust.
 Referenced the implementation of xattr in [unix](golang.org/x/sys/unix) repo.  
 
 Please import and use this project.
+
+```console
+$ cargo run
+```

experiment/selinux/src/main.rs

@@ -0,0 +1,43 @@
+use anyhow::Result;
+use selinux::selinux::*;
+use selinux::selinux_label::*;
+use std::fs::File;
+use std::path::Path;
+
+fn main() -> Result<()> {
+    let mut selinux_instance: SELinux = SELinux::new();
+
+    if selinux_instance.get_enabled() {
+        println!("selinux is enabled");
+    } else {
+        println!("selinux is not enabled");
+
+        match selinux_instance.set_enforce_mode(SELinuxMode::PERMISSIVE) {
+            Ok(_) => println!("set selinux mode as permissive"),
+            Err(e) => println!("{}", e),
+        }
+    }
+    println!(
+        "default enforce mode is: {}",
+        selinux_instance.default_enforce_mode()
+    );
+    println!(
+        "current enforce mode is: {}",
+        selinux_instance.enforce_mode()
+    );
+
+    match selinux_instance.current_label() {
+        Ok(l) => println!("SELinux label of current process is: {}", l),
+        Err(e) => println!("{}", e),
+    }
+
+    let file_path = Path::new("./test_file.txt");
+    let _file = File::create(file_path)?;
+    let selinux_label =
+        SELinuxLabel::try_from("unconfined_u:object_r:public_content_t:s1".to_string())?;
+    SELinux::set_file_label(file_path, selinux_label)?;
+    let current_label = SELinux::file_label(file_path)?;
+    println!("file label is {}", current_label);
+
+    Ok(())
+}

experiment/selinux/src/selinux.rs

@@ -1,6 +1,6 @@
 use crate::selinux_label::SELinuxLabel;
 use nix::errno::Errno;
-use nix::sys::{statfs, statvfs};
+use nix::sys::statfs;
 use nix::unistd::gettid;
 use std::collections::HashMap;
 use std::convert::From;
@@ -44,7 +44,12 @@ impl From<&str> for SELinuxMode {
 
 impl fmt::Display for SELinuxMode {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "{}", *self as i32)
+        let s = match self {
+            SELinuxMode::ENFORCING => "enforcing",
+            SELinuxMode::PERMISSIVE => "permissive",
+            SELinuxMode::DISABLED => "disabled",
+        };
+        write!(f, "{}", s)
     }
 }
 
@@ -211,10 +216,11 @@ impl SELinux {
         loop {
             match statfs::statfs(mnt) {
                 Ok(stat) => {
-                    // verify if the file is readonly or not
-                    if !stat.flags().contains(statvfs::FsFlags::ST_RDONLY) {
-                        return false;
-                    }
+                    // In go-selinux, return false if it is not read-only,
+                    // but selinux code in SELinuxProject return true even though it is read-only.
+                    // https://github.com/SELinuxProject/selinux/blob/1f080ffd7ab24b0ad2b46f79db63d62c2ae2747c/libselinux/src/init.c#L44
+                    // Therefore, this function doesn't check whether it is read-only or not.
+
                     // verify if the file is SELinux filesystem
                     return stat.filesystem_type() == statfs::SELINUX_MAGIC;
                 }

experiment/selinux/src/selinux_label.rs

@@ -77,10 +77,7 @@ impl SELinux {
                 // When a system call is interrupted by a signal, it needs to be retried.
                 Err(XattrError::EINTR(_)) => continue,
                 Err(e) => {
-                    return Err(SELinuxError::SetFileLabel(format!(
-                        "set_xattr failed: {}",
-                        e
-                    )));
+                    return Err(SELinuxError::SetFileLabel(e.to_string()));
                 }
             }
         }
@@ -104,10 +101,7 @@ impl SELinux {
                 // When a system call is interrupted by a signal, it needs to be retried.
                 Err(XattrError::EINTR(_)) => continue,
                 Err(e) => {
-                    return Err(SELinuxError::LSetFileLabel(format!(
-                        "lset_xattr failed: {}",
-                        e
-                    )));
+                    return Err(SELinuxError::LSetFileLabel(e.to_string()));
                 }
             }
         }

experiment/selinux/src/tools/xattr.rs

@@ -16,6 +16,7 @@ pub enum XattrError {
     EINTR(i32),
 }
 
+// SELinux label is not so big, so we allocate 1024 bytes for the buffer.
 const INITIAL_BUF_SIZE: usize = 1024;
 
 pub trait PathXattr {
@@ -25,11 +26,15 @@ pub trait PathXattr {
     fn lget_xattr(&self, attr: &str) -> Result<String, XattrError>;
 }
 
-impl PathXattr for Path {
+impl<P> PathXattr for P
+where
+    P: AsRef<Path>,
+{
     // function similar with setxattr in golang.org/x/sys/unix repo.
     // set_xattr sets extended attributes on a file specified by its path.
     fn set_xattr(&self, attr: &str, data: &[u8]) -> Result<(), XattrError> {
-        match rfs::setxattr(self, attr, data, rfs::XattrFlags::CREATE) {
+        let path = self.as_ref();
+        match rfs::setxattr(path, attr, data, rfs::XattrFlags::CREATE) {
             Ok(_) => Ok(()),
             Err(e) => {
                 let errno = e.raw_os_error();
@@ -44,7 +49,8 @@ impl PathXattr for Path {
     // function similar with lsetxattr in golang.org/x/sys/unix repo.
     // lset_xattr sets extended attributes on a symbolic link.
     fn lset_xattr(&self, attr: &str, data: &[u8]) -> Result<(), XattrError> {
-        match rfs::lsetxattr(self, attr, data, rfs::XattrFlags::CREATE) {
+        let path = self.as_ref();
+        match rfs::lsetxattr(path, attr, data, rfs::XattrFlags::CREATE) {
             Ok(_) => Ok(()),
             Err(e) => {
                 let errno = e.raw_os_error();
@@ -59,12 +65,12 @@ impl PathXattr for Path {
     // function similar with getattr in go-selinux repo.
     // get_xattr returns the value of an extended attribute attr set for path.
     fn get_xattr(&self, attr: &str) -> Result<String, XattrError> {
-        // SELinux label is not so big, so we allocate 1024 bytes for the buffer.
+        let path = self.as_ref();
         let mut buf_size = INITIAL_BUF_SIZE;
         let mut buf = vec![0u8; buf_size];
 
         loop {
-            match rfs::getxattr(self, attr, &mut buf) {
+            match rfs::getxattr(path, attr, &mut buf) {
                 Ok(size) => {
                     if size == buf_size {
                         buf_size *= 2;
@@ -85,12 +91,12 @@ impl PathXattr for Path {
     // function similar with lgetxattr in go-selinux repo.
     // lget_xattr returns the value of an extended attribute attr set for path.
     fn lget_xattr(&self, attr: &str) -> Result<String, XattrError> {
-        // SELinux label is not so big, so we allocate 1024 bytes for the buffer.
+        let path = self.as_ref();
         let mut buf_size = INITIAL_BUF_SIZE;
         let mut buf = vec![0u8; buf_size];
 
         loop {
-            match rfs::lgetxattr(self, attr, &mut buf) {
+            match rfs::lgetxattr(path, attr, &mut buf) {
                 Ok(size) => {
                     if size == buf_size {
                         buf_size *= 2;